A top British expert has attacked his government's handling of pre-war intelligence on Iraq by describing it as 'misleading'.

Dr Brian Jones, who headed the Defence Intelligence Staff's nuclear, chemical and biological branch until a year ago, says he does not know of a single expert who backed Prime Minister Tony Blair's case for going to war.

Commenting on the vital claim that Saddam Hussein could have unleashed weapons of mass destruction within 45 minutes, Dr Jones says there is no proof that the single source behind it had 'established a track record of reliabiity'.

In his hardhitting views published in a daily newspaper, Dr Jones adds it would be a 'travesty' ifintelligence staff were blamed for decisions made last year to justify the reasons for going to war.

His assessment that 'expert intelligence analysts' were overruled 'resulting in a presentation that was misleading about Iraq's capabilities' comes less than 24 hours after Blair ordered a six-month investigation headed by former Cabinet Secretary Lord Butler into whether British intelligence was accurate into the run up to the Iraq war.

On Tuesday the British Foreign Office agreed that UK's joint intelligence committee warned last March that 'the intelligence on the timing of when Iraq might use chemical and biological weapons was sparse'.

"Intelligence indicating that chemical weapons remained disassembled and that Saddam had not yet ordered their assembly was highlighted," the JIC report said.

It also said the 750km range al-Hussein ballistic missiles, which it had warned could reach British bases in Cyprus, 'remained disassembled and that it would take several days to assemble them'.

The Foreign Office admission comes on the heels of a senior Israeli politician's claim that his country's intelligence agency, Mossad, knew before the war that the 45-minute claim was 'an old wives' tale' but decided against telling Britain or the United States.

In another blow to the British government, US Secretary of State Colin Powell has said he does not know whether he would have recommended an invasion of Iraq if he had been told it had no stockpiles of banned weapons.

Aides to Prime Minister Blair continue to insist that the disclosures had no impact on the case for war made in the UK government's controversial September 2002 dossier.